Radio transmitting system



Dec. 13, 1927. 1,652,516

F. CONRAD RADI O TRANSMITTING SYSTEM Filed. Dec. 2.5. 1924 INVENTORATTORNEY Patented Dec. 13, 1927.

ream; oo RAnfFor' massages; rENNsYL-VAN A, AssiGNoit T 'wnsrmenousnfntn'o'rnrc' a MANUFACTURINGCOMPANY, A consensus-abs PENNSYLVANIA.

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ii A p pii cationIfiI'ed- December 23, 1924. "Seria1' I iIoQ75 Z581iMyinvention relates' to radio signalling systems, and particularly ,toa.construction i .for a "power: connection between. an oscillationradiator and an oscillation generator.

degree of couplingbetween airoscillation generator and an Oscillationradiator.

' Anotherobject of'my invention is toprovide a connecting devi'ce thatis adapted, to prevent the transfer of oscillatory energy at frequencieshigher than quency.

ZAnOther object In the prior constructionof radio-send in'gapparatus, ithas been common-to construct 'an oscillation radiator comprisingan Nantenna and a counterpoise with a connecto .the h gher harmon cfrequenclestion therebetween, in which may be provided a coiledinductance. It has also been customary to construct an oscillationgenerator in which triodes and suit-ably connected inductances,capacitances and power sources cause the development of radio frequencyoscillations. It has been customary further to position the coiledinductance, in the C11- cuit connecting the antenna and counterpoise,'in inductive relation to the inductance comprisinga portion of theoscillation generator, thus obtaining-a transfer of energy therebetweenby means of magnetic coupling. This construction has been foundob-cjectionable because of the necessity either of bringing a portion of theradiator circuit withinthe building housing the oscillation generator,or of mounting the inductance ofthe oscillation generator at apositionwitlr' out the housing structure in order to obtain 'thenecessary magneticcoupling.

In my previously filed appllcatlon, Serial No. 666,703, filed Oct. 5,1924, and assigned to the Westinghouse Electric and'Manuf acturingCompany, I disclose a construction for a radio sending apparatus inwhich an antenna and counterpoise are provided, connected by aninductance and energized by an oscillation generator of the usual type,connection therebetween being made by a conductor and an interposedvariable con-'- denser. The resent construction contaming the capacitiveconnection has been found the, fundamental freof my invention is to pro:vide' means for reducing the current ,value a required to .transmit agivenkamount of ,en- -i, 4 ergy from j an oscillation generator to an OSA cillation radiator. i

types which advantages are listed in that'dis- N one of thep'reviouslyutilized radiosend- "An object of .my inventionis to providea radio signalling device forcontrolling the ing systems, however,provide satisfactory stopping means for preventing the transfer of oscllat on harmon cs higher than the fundamental oscillation frequency tothe anthe system of my previously mentioned disclosure. It is known thatthe impedance of a condenser varies inversely as the he 7 quency, andthat the impedance of an inductance varies, directly as 3 the frequency.

Because of thisfactpthe inductance, when 7 adjusted to interposethe sameimpedance to the fundamental frequency of oscillation as wouldbeinterposed by a condenser similarly placed, nterposes amuch highermpedance By reason of thischaracteristic, a much purer frequency issupplied to, and radiated from, the open oscillating system.

' Other objects and structural details of my invention will beapparentfrom the follow- 1 mg description when read in connection withthe accompanying drawing, wherein:

The single figure 1s a diagrammatic representation of an embodiment ofmy invention.

- on the inductance 8 and, a point upon conductor 3 other than theelectrical mid-point of the radiator system by a transfer conductor 12,a. portionof which comprises a coiled inductance 14. j i

In the operation of my device, the open oscillating circuit comprisingthe antenna 1, counterpoise 2, and the inter-connected circuit apparatus3, 4 and 5, may be tuned to the desired frequency by adjustment of theinductance 4;. Likewise, the oscillation generator 6 may be adjusted tosubstantially the same frequency by adjustment of the contact llU pointsupon inductance 8. This adjustment mits the transfer of the only desiredamount of energy to the radiating circuit at the fundan'lcntal:trequency and restricts, very strongly, the transfer of energy athigher frequencies, such as the higher harmonics, thereby resulting in avery desirable purity ol radiation frequency.

It has further been found that the energy transfer between the generatordevice and the radiation device takes place by means of alternatingelectric currents at substantially zero phase displacement passingthroughthe conductor 12 and the inductance 14-. Thus it is possible tomake the conductor 12 and iiuluctance l -l oi much smaller size thanwould otherwise he required.

\Vhile I have shown only oneembtnliment of my invention in theaccompanying drawings, it is capable of various changes andmodifications therefrom Without departing from the spirit thereof, andit is desired,

therefore, that only such limitations shall be placed thereon as areimposed by the prior art or indicated in the appended claims.

I claim as my invention:

1. In combination, a radiating circuit, an

oscillation generator and a connection between them, the oscillationgenerator includ ing a closed tuned circuit and means for maintainingoscillations therein and the connection extending from a point in saidclosed circuit to an intern'iediate point in said radiating circuit nearbut not at the mid-point thereof and including an inductive reactance.

2. In combination, an oscillation generator including a closed tunedcircuit determining the frequency of the oscillations and a vacuum tubedevice cooperating with said circuit to maintain said oscillations, aradiating circuit comprising open capacitiveelements and a connectinginductive element as- SULlZllGtl therewith to form an electricallyoscillating system having the same frequencyas said closed tunedcircuit, a connection i'rom said closed circuit to a point near avoltage node of said radiating circuit wherey by the connection may beof small size and a device in said connection for preventing thetransfer oi energy or harmonic direquency. i

.In testimony whereof, I have hereunto suhscribed my name this. 113thday of December,

FRANK CONRAD.

